1. Field of the Invention
This invention relates to a semiconductor device and more particularly to an improvement of a connection structure between a dynamic RAM (DRAM) unit and its redundancy circuit in a semiconductor device.
2. Description of the Related Art
Various redundancy structures have been applied to many semiconductor devices, particularly to those with a large scale integration such as DRAM and the like, for improving yield and for programming the integrated circuit-system. A redundancy structure for a DRAM is so constructed that each memory unit is provided with a peripheral circuit (hereafter called a redundancy circuit) and a polysilicon fuse is interposed at a connection between the redundancy circuit and the memory unit. At least one fuse is cut off by laser-beam heating to desirably program and assemble the redundancy circuit.
The above programming of the redundancy circuit by the use of the polysilicon fuse encounters a problem is that it requires an exclusive and special apparatus for laser-beam heating.
The present invention has been accomplished under the above circumstance. An object of the invention is to provide a semiconductor device wherein a programming of a redundancy circuit can easily be operated without using the above special apparatus.